Black area on my 3d model. How would I fix this?
Select all your Faces and press  Ctrl  +  N  (Recalculate Normals)

These faces face the wrong direction, in fact they point towards the inside of the grip. This sometimes happens when you manually conect faces but it's no problem at all.

In case this doesn't work and some faces still point to the inside you can select those manualy and press  Ctrl +  F , then select "Flip Normals".